graham



y 1938- A. B. GRAHAM METHOD OF EXTRUDING METALS AND ALLOYS Filed April 25. 1955 INVENTOR ATTORNEYS UNITED STATES PATENT OFFICE 2.123.410 mrrnon or nxrnunmc METALS aim more Alexander Barbour Graham, Thornliebank, Glass w, Scotland, assignor to The International Nickel Company, Inc., New York, N. I, a corporation of Delaware Application April 25, 1935, Serial No. 18,130 In Great Britain May 1, 1934 2 Claims. (Cl. ZW-IO) The present invention relates to a method of Broadly stated, the invention contemplates the extruding metals and alloys, and more particuheating in a thin walled metallic container of larly-to a method of producing articles, such as pieces or powder of a metal or of an alloy, prefbillets, rods, tubes, shapes or the like of metal erably under the influence of a non-oxidizing 5 or metal alloys by extrusion. atmosphere, especially a reducing atmosphere, to 5 It is well known that heretofore, it has been a temperature sufilciently high to effect subsethe usual practice to cast a metal or alloy-into quent coalescence of the pieces or powder under an ingot which is to-be extruded, and often to pressure but below the melting temperature of machine this ingot or a billet rolled therefrom the metal or alloy. After heating the pieces or until it fits the extrusion container. Certain powder to such a temperature under the afore- 10 shortcomings, limitations and disadvantages are said condition, the heated pieces or powder and inherent in the aforesaid process. Although atthin walled container are transferred to an extempts have been made toremedy the situation trusion chamberof an extrusion press while preand to provide a more economical procedure, no venting the oxidization of the heated metal or proposal as far as I am aware'has been wholly alloy. In the extrusion press,pressure is applied 15 satisfactory and successful, particularly when to the heated pieces or powder preferably under conducted on an industrial scale for the manuthe influence of a non-oxidizing atmosphere, esfacture of commercial acceptable products. pecially a reducing atmosphere to such an ex- I have discovered that pieces or powder of tent that the heated pieces or powder of metal metal or metal alloys if heated in a thin walled or alloy will coalesce and that billets, rods, tubes, 0 metallic container to a temperature below the shapes or the like can be extruded directly from melting temperature of such materials can be the extrusion press or chamber. In this manner, extruded directly from an extrusion press or the aforesaid articles can be produced directly chamber and that the initial materials will then from initial .pieces or 'powder of a metal or an coalesce so that billets, rods, tubes, shapes or the alloy which, heretofore it has been thought im- 25 like can, in effect, be psroduced directly from inpossible and which heretofore it has been thought itial materials which-it has hitherto been thought necessary to melt the pieces or powder and to cast necessary to melt and treat as described above the same into an ingot or billet which had to be prior to extruding. rolled or worked to size in order to fit the ex- It is. an object of the invention to provide a trusion chamber. In certain instances, it was 30 simple, economical and practical procedure of even necessary to machine the ingot or billet. extruding metals and alloys into various articles. All of these prior operations have now been dis- It is another object of the invention to procovered to be unnecessary and the present invenvide relatively singile and compact apparatus for tion provides the art with a simplified procedure.

carrying the procedure into practice. The term "pieces is intended to include shot, 35

The invention also contemplates the provision turnings, shavings and scrap of all kinds suitof a practical procedure for producing articles able for the production of billets and so forth. like billets, rods, shapes, tubes or the like from In order to obtain complete homogeneity, the metals and alloys by direct extrusion from pieces surfaces of the pieces or powder must be made 40 or powder of metals and alloys. clean initially and kept as clean as possible dur- 40 is Other objects and advantages of the invention .ing the extrusion. If this is not done, that is to will become apparent from the following descripsay if any oxide film or scale is left or allowed tion taken in conjunction with the accompanyto form on the surfaces, it may be impossible to ing drawing in which: produce a coherent or usable article. Fig. l is a side elevation, partly in section and a The invention is of particular value in the pro 45 diagrammatic in character, of an embodiment duction of articles from metals or alloys that are of the novel apparatus for carrying the new normally diillcult to extrude and particularly process into practice; from pieces or powder consisting of or containing Figs. 2 and 3 are views similar to Fig. 1 shownickel. ing various stages of the process; The heating of the pieces or powder may, if 50 Fig. 4 is a modified embodiment of an apdesired, be eifected in an auxiliary container and paratus to carry the present invention into pracmeans may be provided for transferring the pieces tice; and or powder from this auxiliary container to the l Fig. 5 is similar to Fig. 4 and shows the apps.- extrusion chamber without subjecting them to v 65 ratus in another stage. a oxidation. Further, the auxiliary container may be arranged either outside or inside the extrusion press. In the former case the auxiliary container may advantaseously incorporate an electrical shown in Figs. 4 and 5, the particles contained heating element and be arranged to move between 5 a positionin which it co-operates with a charging hopper or the like and a position in which it is in register with the extrusion chamber to discharge its contents. Again, the auxiliarycontainer may communicate with the extrusion con-' chamber. If the heating is to take place in the in the extrusion container or chamber electrically by means of high frequency induction, or similarly in an auxiliary container placed directly above the extrusion container or chamber and arranged so that, when heating of the contents is complete, these are allowed to drop into the extrusion container or chamber. The extrusion press-ram may either work through this heating container, or the heating container may be removed out of the way whilst extrusion takes place.

The powder or pieces may be heated in a thin walled container outside the extrusion press by any suitable means, for example, in a fuel-fired furnace or by a high frequency electrical method, this container then being transferred bodily with its contents to the press. The thin-walled container may then be extruded with the pieces or powder and either allowed to remain on the resultant extruded article as a cladding skin or removed by turning. Alternatively, the dimensions of thethin-walled container, the extrusion container or chamber and the press-ram maybe so chosen that the thin-walled container acts in 4L effect as a liner for the extrusion container or chamber.

The improved process may be carried into practice in any appropriate equipment butit is preferred to use the apparatus illustrated in the drawing.

Referring to the embodiment of the invention illustrated in Figs. 1 to 3, the powder or pieces of metal I are held in a thin walled metal container 2 which may completely enclose the powder or pieces or which may be open at the end, said container being placed in a block 3 which can slide on a table 4. This block I is formed with a 'central opening containing a liner 5 which is surrounded by an electric element serving to heat metal in the liner 5, for example, by high frequency induction. Appropriate means may be employed for maintaining a non-oxidizing atmosphere, especially one reducing in character, in the auxiliary chamber.

When the desired temperature has bee reached, the whole block 3 is slid into position in the extrusion press by being pushed from the position shown in Fig. l to theposition shown in Fig. 2, in which it lies above an extrusion container orchamber I and beneath a press ram 8. An extrusion opening {is provided at the bottom of the extrusion container or chamber I. The pieces and thin walled container drop out of the block 3 into the extrusion container or chamber I, which is then moved back into its initial position as shown in Figure 3, while the press ram I is then brought down so that the metal is extruded through the opening I; As those skilled in the art will readily understand, appropriate means may be employed for maintaining s. nonpress itself, the pieces or powder may be heated oxidising atmosphere, one reducing in character, in the extrusion chamber.

In the modified embodiment of the apparatus,

in a thin walled metallic container may be heated in any suitable furnace or by any suitable means, as those skilled in the art will readily understand instead of by the electrical heating unit shown in Figs. 1 to 3 before transferring to an extrusion press. The container 2 is transferred bodily with its contents I toan extrusion press as shown in Fig. 4. The heated container is then dropped .into extrusion chamber I and press ram I is brought downto the position shown in Fig. 5 so that the metal is extruded through orifice opening I. Appropriate means may be employed for maintaining a non-oxidizing atmosphere, especially one reducing in character, in the extrusion chamber as those skilled in the art will readily understand.

The apparatus illustrated in Fig. 1 may be modified by providing two or more extrusion chambers on onev turntable arranged to rotate so as to bring each container in succession beneath the press ram, or again auxiliary heating containers may be provided in a turntable arranged to bring each in succession into register with the press ram and extrusion container or chamber. In either of these last two cases, the metal or metal alloy-canbe heated in one or more extrusion containers or chambers or auxiliary heating containers while extrusion is proceeding from another.

If grains of powder or very small pieces are,

used, they must be prevented from running out of the hole at the bottom or end of the extrusion container or chamber before extrusion begins. and accordingly the end of the container. or chamber may be arranged to be closed mechanically, for instance. where an open ended thin walled container is used, or by a plug M or by a disc or similar piece of the metal or metal alloy to be extruded, forming, for example, the end wall of the thin walled metallic container. Moreover, if it is desired to compress the pieces or powder to some extent before extrusion proper begins, this closure will allow this to be done.

The invention may be applied not only to powder in which all the Brains are free from one another, but to powder that has been sintered, for example, in a thin walled metal container, into the form of a block or blocks that will readily flt into the extrusion container or chamber. Such sintered blocks may be transferred hot to the extrusion press direct from the sintering chamber and converted into extruded solid attlcles in accordance with the invention, or they may be allowed to cool and be reheated prior to extrusion.

In the case of alloys, metal turnings or other scrap of the alloy in question may advantageously be used. However, the invention may also be applied to the production of alloys. In such a case, the ingredients from which the alloy is to be formed are placed in powdered form in a thin walled metal container in the extrusion press and in order to obtain the desired homogeneity the resultant extruded article may be annealed for a substantial time in order to allow the metals to difluse into one another.

It will be understood that in every case the temperature of extrusion will depend on the in which it is used, and that, while it must be sufficient to render the metal or alloy extrudible,

a metal or alloy in question and also on the form it must be below that at which the metal or alloy begins to melt. Thus in thecase of nickel shot such, for example, as the pellets produced by the well-known Mond nickel carbonyl process, the temperature may be about 1150 C., while in the case of nickel} powder, such, for example, as may be produced by the direct reduction of nickel oxide or salts, or by the decomposition of nickel carbonyl under conditions that prevent the formation of nickel shot, the temperature may be about 1220 C. Alloys of copper and nickel are preferably heated to a somewhat lower temperature, such as 1060 C., and nickel-silver alloys to a lower temperature still, such as 750 C. Nickel-iron powder, on the other hand, needs a higher temperature, such as 1200 C.

I claim:'

1. A process of producing an article constituted of nickel or nickel alloy which comprises heating a mass of nickel containing particles in a thin-walled metallic container to a selected temperature below the melting point 01' said mass and said container, transferring said container bodily to an extrusion chamber, and then extruding said heated container from an extrusion chamber whereby coalescence of the particles is effected and an integral nickel article is produced.

2. A process of producing an article constituted of nickel or nickel alloy which comprises electrically heating by means of high frequency induction nickel containing particles in a thinwalled metallic container to a temperature within a range of about 750 C. to about 1220 0., transferring said container bodily to an extrusion chamber through a reducing atmosphere, and then extruding said heated container from an extrusion chamber whereby coalescence of the particles is effected and an integral nickel article is produced.

ALEXANDER HARBOUR GRAHAM. 

